Simon
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Registered: 24th Apr 03
Location: Oxfordshire
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In a couple of weeks I'm going to knock up some miniature greenhouses down my allotment using some old windows. My Plan is to erect these in a polygon shape over a raised planting bed.
So it should be a miniature version of something like this:
I'm going to get some sheet plastic to use for the roof. What I'm after is if there is a maths equation or working out I can use to work out the size I would need to cut each triangular section for the roof?
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AndyKent
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Registered: 3rd Sep 05
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Draw a plan (top down) view of the roof, work out what height you're going to have the roof, then pythagoras to work out length of sheet.
Unless I've misunderstood.
[Edited on 10-04-2011 by AndyKent]
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Ian
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Registered: 28th Aug 99
Location: Liverpool
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You would only use a top down view if you wanted a flat roof.
Pythagoras will work in 3D but you will need to half the length of the bottom edge in the calculation because they're isosceles triangles not right-angled.
Also worth knowing whether you already know the width of the vertical panels and that is your constraint on building it, or you want to most effectively use the plastic sheets with minimal wastage.
Also is the height of the peak decided?
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Simon
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Registered: 24th Apr 03
Location: Oxfordshire
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I'm building two of them, but will be different sizes due to the assortment of windows I've collected.
Now I've thought about it, I think I've got my head around it. Might knock up a 3D model of it and then get the size and angles of that. Heights aren't decided yet, will want to try and get as many bits out of each sheet though, spending as little as possible on this
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Ian
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Registered: 28th Aug 99
Location: Liverpool
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You don't need a model, you can use Pythag to work out the edges or polynomial zeroes to find the most effective way of using up the sheets.
When you say different sizes for the vertical panels, do you mean per building or each building comprising of a number of different panels, ie. not an equilateral polygon when viewed from above. The latter having scalene triangles in the roof section which makes thing more complicated.
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Simon
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Registered: 24th Apr 03
Location: Oxfordshire
User status: Offline
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Each one will be equilateral, that would be a pain in the arse to work out. I modeled it in sketchup in 2mins and measures the angles. You lost me on polynomial zeroes 
Thanks for help though
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